1. Field of the Invention
The invention relates to a deceleration control apparatus and method for a vehicle. More particularly, the invention relates to a deceleration control apparatus and method for a vehicle, which controls deceleration of the vehicle by an operation of a brake system which applies braking force to the vehicle and a shift operation that shifts an automatic transmission into a relatively low speed.
2. Description of the Related Art
JP(A) 10-132072 discloses technology which detects the current position of a vehicle and an upcoming curve, searches for a recommended speed that will enable the vehicle to travel smoothly through the upcoming curve, and decelerates the vehicle to the recommended speed when entering or going into the curve using the engine brake by downshifting into a lower speed when it has been detected that the accelerator pedal has been released.
When shift point control is performed in a stepped automatic transmission in order to apply a predetermined deceleration to the vehicle according to the size of the corner, it may not be possible to apply the optimum deceleration to the vehicle. For example, often times the speed selected by the shift point control (i.e., the downshift amount) is set to always be the same for the same corner size, vehicle speed, and current speed, regardless of the distance from the location at which it was detected that the accelerator pedal was released to the corner. As a result, it is often not possible to have the optimum deceleration be applied to the vehicle.
In JP(A) 10-132072, a downshift is triggered by the release of the accelerator pedal. However, unless there is a brake operation for further deceleration by the driver, the target deceleration is left unchanged and the vehicle will travel through the curve at a speed higher than the recommended speed. In this way, a vehicle may enter a curve in a deceleration state that does not match the suitable recommended speed, which may result in riding discomfort.